Learned from @​fontana@​identi.ca about the Sun LGPL Disclaimer and immediately had to look it up. First search hit:

http://www.virtualbox.org/svn/vbox/trunk/src/VBox/Additions/WINNT/Graphics/Wine/include/rtutils.h

This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version.

Ok, that's pretty clear, the standard LGPL2.1+ header. But then comes this:

Sun LGPL Disclaimer: For the avoidance of doubt, except that if any license choice other than GPL or LGPL is available it will apply instead, Sun elects to use only the Lesser General Public License version 2.1 (LGPLv2) at this time for any software where a choice of LGPL license versions is made available with the language indicating that LGPLv2 or any later version may be used, or where a choice of which version of the LGPL is applied is otherwise unspecified.

Avoidance of doubt? After reading this five times, it still doesn't parse.

After some more mulling over this, I have the hunch that they are saying "we're not really sure what license this software is under, because this is a standard disclaimer, but if we have the choice, this is distributed under any other license than GPL or LGPL, or, if we only have a choice of LGPL versions, this is distributed under LGPL2.1-only".

Is my reading correct? I still have my doubts.